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Impacts of monsoon break events in the western North Pacific on the cross-equatorial flows over the Maritime Continent
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作者 Xiaoxuan Zhao Minghao Bi +2 位作者 Ke Xu Jianqi Sun Riyu Lu 《Atmospheric and Oceanic Science Letters》 CSCD 2024年第2期33-38,共6页
本文利用ERA5逐日再分析资料,探讨了1979-2020年间西北太平洋季风中断事件对海洋性大陆越赤道气流的影响.合成结果表明,西北太平洋季风中断事件会造成高,低空越赤道气流减弱,即高层南风异常,低层北风异常,与此相关的环流异常表现为西北... 本文利用ERA5逐日再分析资料,探讨了1979-2020年间西北太平洋季风中断事件对海洋性大陆越赤道气流的影响.合成结果表明,西北太平洋季风中断事件会造成高,低空越赤道气流减弱,即高层南风异常,低层北风异常,与此相关的环流异常表现为西北太平洋高层气旋,低层反气旋的斜压结构。特别的是,西北太平洋季风中断对高空越赤道气流的影响更为显著,92%的季风中断事件都导致高空越赤道气流减弱,而只有70%的事件造成低空越赤道气流减弱,这是由于低空越赤道气流同时还受到赤道中东太平洋海温异常的调控. 展开更多
关键词 西北太平洋夏季风 季风中断 越赤道气流 海洋性大陆
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Variations of the Summer Somali and Australia Cross-Equatorial Flows and the Implications for the Asian Summer Monsoon 被引量:18
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作者 祝亚丽 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2012年第3期509-518,共10页
The temporal variations during 1948-2010 and vertical structures of the summer Somali and Australia cross-equatorial flows (CEFs) and the implications for the Asian summer monsoon were explored in this study. The st... The temporal variations during 1948-2010 and vertical structures of the summer Somali and Australia cross-equatorial flows (CEFs) and the implications for the Asian summer monsoon were explored in this study. The strongest southerly and northerly CEFs exist at 925 hPa and 150 hPa level, respectively. The low-level Somali (LLS) CEFs were significantly connected with the rainfall in most regions of India (especially the monsoon regions), except in a small area in southwest India. In comparison to the climatology, the low- level Australia (LLA) CEFs exhibited stronger variations at interannual time scale and are more closely connected to the East Asian summer monsoon circulation than to the LLS CEFs. The East Asian summer monsoon circulation anomalies related to stronger LLA CEFs were associ- ated with less water vapor content and less rainfall in the region between the middle Yellow River and Yangtze River and with more water vapor and more rainfall in southern China. The sea-surface tempera- ture anomalies east of Australia related to summer LLA CEFs emerge in spring and persist into summer, with implications for the seasonal prediction of summer rainfall in East Asia. The connection between the LLA CEFs and East Asian summer monsoon rainfall may be partly due to its linkage with E1 Nino-Southern Oscillation. In addition, both the LLA and LLS CEFs .exhibited interdecadal shifts in the late 1970s and the late 1990s, consistent with the phase shifts of Pacific Decadal Oscillation (PDO). 展开更多
关键词 cross-equatorial flow Asian summer monsoon low-level jet SOMALI
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Water Vapor Transport and Cross-Equatorial Flow over the Asian-Australia Monsoon Region Simulated by CMIP5 Climate Models 被引量:7
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作者 宋亚娟 乔方利 +1 位作者 宋振亚 姜春飞 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2013年第3期726-738,共13页
The summer mean water vapor transport (WVT) and cross-equatorial flow (CEF) over the Asian- Australian monsoon region simulated by 22 coupled atmospheric-oceanic general circulation models (AOGCMs) from the Worl... The summer mean water vapor transport (WVT) and cross-equatorial flow (CEF) over the Asian- Australian monsoon region simulated by 22 coupled atmospheric-oceanic general circulation models (AOGCMs) from the World Climate Research Programme's Coupled Model Intercomparison Project Phase 5 (CMIP5) were evaluated. Based on climatology of the twentieth-century simulations, most of models have a reason- ably realistic representation of summer monsoon WVT characterized by southeast water vapor conveyor belt over the South Indian Ocean and southwest belt from the Arabian Sea to the East Asian. The correlation coefficients between NCEP reanalysis and simulations of BCC-CSMI-1, BNU-ESM, CanESM2, FGOALS-s2, MIROC4h and MPI-ESM-LR are up to 0.8. The simulated CEF depicted by the meridional wind along the equator includes the Somali jet and eastern CEF in low atmosphere and the reverse circulation in upper atmosphere, which were generally consistent with NCEP reanalysis. Multi-model ensemble means (MME) can reproduce more reasonable climatological features in spatial distribution both of WVT and CEF. Ten models with more reasonable WVT simulations were selected for future projection studies, including BCC- CSMI-1, BNU-ESM, CanESM2, CCSM4, FGOALS-s2, FIO-ESM, GFDL-ESM2G, MRIOCS, MPI-ESM-LR and NorESM-1M. Analysis based on the future projection experiments in RCP (Representative Concentra- tion Pathway) 2.6, RCP4.5, RCP6 and RCP8.5 show that the global warming forced by different RCP scenarios will results in enhanced WVT over the Indian area and the west Pacific and weaken WVT in the low latitudes of tropical Indian Ocean. 展开更多
关键词 CMIP5 AOGCMs water vapor transport cross-equatorial flow future projection
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Vertical Structure of Interannual Variability in Cross-Equatorial Flows over the Maritime Continent and Indian Ocean in Boreal Summer 被引量:1
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作者 Xiaoxuan ZHAO Riyu LU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2020年第2期173-186,共14页
This study investigates the vertical structure of variability in the cross-equatorial flows(CEFs)over the Maritime Continent and Indian Ocean in boreal summer,based on three reanalysis datasets:ERA-Interim,JRA-55 and ... This study investigates the vertical structure of variability in the cross-equatorial flows(CEFs)over the Maritime Continent and Indian Ocean in boreal summer,based on three reanalysis datasets:ERA-Interim,JRA-55 and NCEP-2.The results show a high consistency in the interannual variability among the reanalysis datasets,especially between ERAInterim and JRA-55,while great uncertainty exists in the decadal or long-term changes of CEFs.Further analyses on the interannual variability in CEFs indicate that there is a significant negative relationship between the upper-and lower-level CEFs over the Maritime Continent—that is,the northerlies at the upper level and southerlies at the lower level are both enhanced or weakened.This seesaw pattern is also significantly related to the CEFs over the Indian Ocean at the upper level and lower level(i.e.,the Somali jet).This close relationship between the upper-and lower-level CEFs and between the Maritime Continent and Indian Ocean is manifested as the leading mode of equatorial meridional winds in the vertical-zonal section over the Maritime Continent and Indian Ocean.Finally,it is found that ENSO is closely related to the vertical leading mode,and to all the CEFs at the upper and lower levels over the Maritime Continent and Indian Ocean. 展开更多
关键词 cross-equatorial flows vertical structure interannual variability ENSO
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NUMERICAL SIMULATION OF SSTA IMPACTS UPON THE INTERDECADAL VARIATION OF THE CROSS-EQUATORIAL FLOWS IN EASTERN HEMISPHERE 被引量:2
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作者 曾刚 孙照渤 +2 位作者 邓伟涛 林朝晖 李春晖 《Journal of Tropical Meteorology》 SCIE 2013年第3期223-232,共10页
Impacts of regional sea surface temperature(SST)anomalies on the interdecadal variation of the cross-equatorial flows(CEFs)in Eastern Hemisphere are studied using numerical simulations with a global atmospheric circul... Impacts of regional sea surface temperature(SST)anomalies on the interdecadal variation of the cross-equatorial flows(CEFs)in Eastern Hemisphere are studied using numerical simulations with a global atmospheric circulation model(NCAR CAM3)driven with 1950-2000 monthly SSTs in different marine areas(the globe,extratropics,tropics,tropical Indian Ocean-Pacific,and tropical Pacific)and ERA-40reanalysis data.Results show that all simulations,except the one driven with extratropical SSTs,can simulate the interdecadal strengthening of CEFs around Somali,120oE,and 150oE that occurred in the midand late-1970s.Among those simulated CEFs,the interdecadal variability in Somali and its interdecadal relationship with the East Asian summer monsoon are in better agreement with the observations,suggesting that changes in the SSTs of tropical oceans,especially the tropical Pacific,play a crucial role in the interdecadal variability of CEFs in Somali.The interdecadal change of CEFs in Somali is highly associated with the interdecadal variation of tropical Pacific SST.As the interdecadal warmer(colder)SST happens in the tropical Pacific,a"sandwich"pattern of SST anomalies,i.e."+,-,+"("-,+,-"),will occur in the eastern tropical Pacific from north to south with a pair of anomalous anticyclone(cyclone)at the lower troposphere;the pair links to another pair of anomalous cyclone(anticyclone)in the tropical Indian Ocean through an atmospheric bridge,and thus strengthens(weakens)the CEFs in Somali. 展开更多
关键词 cross-equatorial flow in EASTERN HEMISPHERE numerical simulation INTERDECADAL variation sea surface temperature ANOMALY
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CLIMATOLOGICAL VARIATION OF GLOBAL CROSS-EQUATORIAL FLOWS FOR THE PERIOD 1948-2004 被引量:2
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作者 施能 封国林 +2 位作者 顾骏强 谷德军 余锦华 《Journal of Tropical Meteorology》 SCIE 2007年第2期201-204,共4页
By using monthly NCEP/NCAR meridional gridpoint wind data at the levels of 1000, 850, 700, 600, 500, 400, 300, 200, 150 and 100 hPa from 1948 to 2004, the intensity of global cross-equatorial flows is calculated. The ... By using monthly NCEP/NCAR meridional gridpoint wind data at the levels of 1000, 850, 700, 600, 500, 400, 300, 200, 150 and 100 hPa from 1948 to 2004, the intensity of global cross-equatorial flows is calculated. The spatial and temporal variation of global cross-equatorial flows at the 850-hPa level are shown and discussed. The results show that the strength of the 850-hPa global cross-equatorial flows represent obvious long-term variation and interdecadal change during the period. Evidence suggests that the cross-equatorial flow of the passages at 45 – 50 °E in June to August, 105 – 115 °E in May to September, 130 – 140 °E in May to September and May to November and 20 – 25 °E in February to April intensified and that the cross-equatorial flow of the passages at 50 – 35 °W in June to August weaken in the past 57 years,with an increase of 0.25m/s/10a for summer Somali Jet and increase of 0.32 m/s/10a for cross- equatorial flow at 130 – 140 °E in May to September The results of Singular Spectrum Analysis (SSA) for the time series indicate that for the cross-equatorial flow at 850 hPa, the interdecadal and long-term trend changes are 35% – 45%, and the interannual variation is no more than 30%, in variance contribution. The results also reveal that the interannual variation of intensity of the summer cross-equatorial flows in the Pacific is significantly correlated with Southern Oscillation. With weak Southern Oscillation, strong cross- equatorial flows in Pacific will happen, though the summer Somali Jet is only a little positively correlated with North Atlantic Oscillation (NAO). 展开更多
关键词 大气环流 赤道仪 光谱 气候变换
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Modulation by the Atlantic Multidecadal Oscillation of the intensity of the interannual seesaw between the Somali and Australian cross-equatorial flows
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作者 LI Shuanglin CHEN Ying LI Chen 《Atmospheric and Oceanic Science Letters》 CSCD 2017年第4期306-311,共6页
夏季索马里越赤道气流与澳大利亚越赤道气流之间存在翘翘板式的反向变化。本文利用NCEP/NCAR月平均再分析资料(1948–2013),分析了这种翘翘板式反向变化强度的年代际演变特征,并讨论了可能原因。结果表明:越赤道气流之间的反向变化强度... 夏季索马里越赤道气流与澳大利亚越赤道气流之间存在翘翘板式的反向变化。本文利用NCEP/NCAR月平均再分析资料(1948–2013),分析了这种翘翘板式反向变化强度的年代际演变特征,并讨论了可能原因。结果表明:越赤道气流之间的反向变化强度在1966年左右和2002年左右分别发生了明显的转折。这种转折与其受ENSO强度的调制有关,在很大程度上可归于大西洋海温长周期年代际振荡(AMO)。因为AMO调制ENSO的强度,故而影响越赤道气流之间翘翘板式反向变化的强度。当AMO处于正(负)位相时,ENSO事件倾向于偏弱(偏强),越赤道气流之间翘翘板式反向变化关系变得相对较弱(较强)。它们三者间的关系在CMIP5历史试验(1860–2005)中依然存在。 展开更多
关键词 越赤道气流 年代际变化 ENSO 大西洋海温长周期年代际振荡(AMO)
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VARIATION FEATURES OF SOMALI CROSS-EQUATORIAL FLOW AND ITS IMPACT ON THE LOCATION OF THE SUBTROPICAL HIGH RIDGE FROM JULY TO SEPTEMBER
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作者 林新彬 许金镜 +2 位作者 温珍治 何芬 池艳珍 《Journal of Tropical Meteorology》 SCIE 2008年第1期15-18,共4页
The variation features of the cross-equatorial flow and its impact on the ridge position of the subtropical high have been analyzed in this paper. It is shown as follows. (1) The intensity of the Somali cross-equatori... The variation features of the cross-equatorial flow and its impact on the ridge position of the subtropical high have been analyzed in this paper. It is shown as follows. (1) The intensity of the Somali cross-equatorial flow is increasing in winter and summer in the past 44 years and the airflow of Northern Hemisphere exchanges more and more intensively with that of Southern Hemisphere. (2) The Somali cross-equatorial flow in May has the most impact on the ridge position of the subtropical high in the typhoon season, presenting a positive correlation. (3) The diagnosis is consistent with the real situation in 2005. 展开更多
关键词 十字赤道仪 亚热带地区 相关性分析 鉴别
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INTERANNUAL VARIATION CHARACTERISTICS OF EAST HEMISPHERIC CROSS-EQUATORIAL FLOW AND ITS CONCURRENT RELATIONSHIPS WITH TEMPERATURE AND RAINFALL IN CHINA
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作者 雷小春 杨修群 《Journal of Tropical Meteorology》 SCIE 2008年第2期97-100,共4页
The NCEP/NCAR global reanalysis data were used to analyze the interannual variation characteristics of the cross-equatorial flow (CEF) and its concurrent relationships with temperature and rainfall in China. The resul... The NCEP/NCAR global reanalysis data were used to analyze the interannual variation characteristics of the cross-equatorial flow (CEF) and its concurrent relationships with temperature and rainfall in China. The results indicated that CEF changes more in summer than in winter. As the main flow channel in summer, the Somali CEF changes in a way that does not markedly influence the changes in the CEF total except for winter. The summer CEF total has two sudden increases and one sudden decrease during the last century while the winter total has just one decrease. Long-period data show that the correlation between CEF and summer rainfall in China is not very significant, but is different before and after the 1970s, which is due to CEF's close links with the East Asia summer monsoon. Winter CEF's correlation with concurrent winter temperature in northern and southern China varies with the relationship between CEF and sea-level pressure in different areas. 展开更多
关键词 天气 气候 远距离地区 相互关系
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Relationship between cross-equatorial flows over the Bay of Bengal and Australia in boreal summer:Role of tropical diabatic heating
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作者 Xuelei Jiang Yuanyuan Guo Zhiping Wen 《Atmospheric and Oceanic Science Letters》 CSCD 2022年第2期1-6,共6页
本文通过对1979–2017年夏季925 h Pa经向风异常进行经验正交函数(EOF)分解,研究了亚澳季风区内越赤道气流的年际变化特征.结果表明,越赤道气流的第一模态表现为亚澳季风区内不同通道间的同相变化,即一致加强或减弱;第二模态表现为孟加... 本文通过对1979–2017年夏季925 h Pa经向风异常进行经验正交函数(EOF)分解,研究了亚澳季风区内越赤道气流的年际变化特征.结果表明,越赤道气流的第一模态表现为亚澳季风区内不同通道间的同相变化,即一致加强或减弱;第二模态表现为孟加拉湾和澳大利亚越赤道气流的反相变化,其中新几内亚和孟加拉湾越赤道气流的反相变化最显著.该反相模态分别对应着赤道以南地区海洋性大陆东西两侧的海温异常,其纬向偶极型的空间分布直接导致海洋性大陆西部(东部)出现沿赤道非对称的异常热汇(热源),它可以激发跨越赤道的南风(北风)异常,从而有利于该反相模态的出现. 展开更多
关键词 越赤道气流 赤道非对称热源 线性斜压模式
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4D-Flow MRI在肥厚型心肌病左室流出道血流评估中的价值探索
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作者 徐晶 陈秀玉 +3 位作者 尹刚 闫伟鹏 陆敏杰 赵世华 《磁共振成像》 CAS CSCD 北大核心 2024年第3期56-61,共6页
目的 探索四维血流(four-dimensional flow,4D-Flow)磁共振成像(magnetic resonance imaging,MRI)技术在左心室腔内应用的可行性。材料与方法 本研究为前瞻性、横断面研究,纳入2022年8月至2023年1月于我院接受心脏MRI检查的21例肥厚型... 目的 探索四维血流(four-dimensional flow,4D-Flow)磁共振成像(magnetic resonance imaging,MRI)技术在左心室腔内应用的可行性。材料与方法 本研究为前瞻性、横断面研究,纳入2022年8月至2023年1月于我院接受心脏MRI检查的21例肥厚型心肌病患者,采用3.0 T MRI扫描仪进行二维血流(tow-dimensional flow,2D-Flow)及4D-Flow成像,收集患者一周内进行的超声心动图检查结果。采用组内相关系数(inter-class correlation coefficient,ICC)、变异系数(coefficients of variation,COV)及Bland-Altman分析比较2D-Flow、4D-Flow评估左室流出道峰值流速的可重复性及一致性,并通过Pearson相关性分析探究二者与超声心动图测量结果的关系。结果 2D-Flow和4D-Flow观察者内/观察者间的ICC分别为0.999/0.999和0.995/0.992,COV分别为0.5%/0.5%和2.4%/2.6%。4D-Flow与超声心动图的测量结果呈中度相关,相关系数r值为0.574(P=0.006),但一致性较差,ICC为0.375(P=0.013)。2D-Flow与4D-Flow和超声心动图间无显著的一致性及相关性。结论 4D-Flow技术能够可视化心腔内血流模式,对左室流出道峰值流速的测量具有高度可重复性,且与超声心动图的测量结果具有显著的一致性。 展开更多
关键词 肥厚型心肌病 四维血流 二维血流 心脏磁共振 磁共振成像
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基于Flow Simulation的某发动机涡轮压气机流场与效率分析
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作者 邹春龙 饶纪元 +1 位作者 邓小雯 孙海明 《内燃机与配件》 2024年第11期13-15,共3页
涡轮机内部流场对涡轮增压器的性能和效率有着重要影响,采用SolidWorks Flow Simulation模块对某发动机涡轮压气机侧流场和压气效率分析。在六种不同空气体积流量工况下,体积流量为0.29时,压气机效率最高,达到80%左右。模型的建模和流... 涡轮机内部流场对涡轮增压器的性能和效率有着重要影响,采用SolidWorks Flow Simulation模块对某发动机涡轮压气机侧流场和压气效率分析。在六种不同空气体积流量工况下,体积流量为0.29时,压气机效率最高,达到80%左右。模型的建模和流体分析均在SolidWorks环境下,分析效率高,为涡轮增压器设计和优化提供了支撑。 展开更多
关键词 涡轮压气机 流场 效率
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肝硬化患者4D flow MRI血流动力学参数与中医证型的相关性研究
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作者 胡勤勤 姜阳 +3 位作者 张玉龙 方玉 梁仁容 杨华 《中国中医急症》 2024年第6期982-985,989,共5页
目的探讨肝硬化患者4D flow MRI血流动力学参数与中医证型的相关性。方法将118例肝硬化患者依据中医辨证分为肝气郁结证、湿热蕴结证、肝肾阴虚证、脾肾阳虚证、瘀血阻络证5个证型,所有患者均行门静脉4D flow MRI检查,统计不同证型肝硬... 目的探讨肝硬化患者4D flow MRI血流动力学参数与中医证型的相关性。方法将118例肝硬化患者依据中医辨证分为肝气郁结证、湿热蕴结证、肝肾阴虚证、脾肾阳虚证、瘀血阻络证5个证型,所有患者均行门静脉4D flow MRI检查,统计不同证型肝硬化患者分布情况,观察门静脉系统(门静脉主干、脾静脉、肠系膜上静脉)的血流动力学参数,包括血流量、流速、壁剪切力等,比较不同证型患者门静脉血流动力学参数差异。结果肝硬化代偿期以肝气郁结证、湿热蕴结证为主,肝硬化失代偿期以脾肾阳虚、瘀血络阻证为主;A级以肝气郁结证、湿热蕴结证为主,B、C级以瘀血络阻证为主。瘀血络阻证肝硬化患者门静脉主干及脾静脉血流量明显高于肝气郁结证、湿热蕴结证患者(P<0.05);脾肾阳虚证门静脉主干血流量明显高于肝气郁结证肝硬化患者(P<0.05);瘀血络阻证肝硬化患者门静脉主干流速及剪切力较肝气郁结证和湿热蕴结证低。结论肝硬化患者中医辨证分型与门静脉血流动力学参数具有一定相关性,4D flow MRI可为肝硬化的中医辨证提供血流动力学参考。 展开更多
关键词 肝硬化 4D flow MRI 血流动力学 中医证型
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基于 Moldflow 的汽车中控台框架翘曲变形分析及优化
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作者 刘巨保 黄建军 +3 位作者 杨明 李峰 张亮 查翔 《塑料工业》 CAS CSCD 北大核心 2024年第3期83-88,共6页
以某汽车中控台框架为研究对象,测量试模样品发现其翘曲变形量超过了装配要求。通过Moldflow软件模拟了该塑件实际的注塑过程,翘曲变形量的模拟值与实测平均值的最大误差为5.98%,发现该塑件翘曲变形的主要因素为冷却不均和收缩不均。本... 以某汽车中控台框架为研究对象,测量试模样品发现其翘曲变形量超过了装配要求。通过Moldflow软件模拟了该塑件实际的注塑过程,翘曲变形量的模拟值与实测平均值的最大误差为5.98%,发现该塑件翘曲变形的主要因素为冷却不均和收缩不均。本文在原物料中添加质量分数为25%的玻璃纤维以及优化工艺参数后,翘曲变形量的模拟值与初始方案相比降低了86.22%。试模验证表明,优化后的翘曲变形量模拟值与实测平均值的最大误差为4.35%,证明了Moldflow软件模拟分析的准确性。试模后各检测点的最大翘曲变形量降到了1.6 mm以下,较优化之前降低了80%以上,为类似大型复杂注塑件的翘曲变形分析及优化提供了思路。 展开更多
关键词 注塑成型 中控台框架 翘曲变形 模流分析 玻璃纤维
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V Flow技术测量颈动脉壁面剪应力的一致性研究
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作者 加依达尔·沙亚哈提 周琛云 陈曼琳 《四川医学》 CAS 2024年第1期28-34,共7页
目的评价血流向量成像(V Flow)技术在测量健康成年人颈动脉壁面剪应力(WSS)中的一致性。方法于2021年2月至2021年3月招募健康成年志愿者20人,由2名不同年资的超声医师使用配备V Flow功能的Mindray Resona 7超声仪和3~9 MHz线阵探头进行... 目的评价血流向量成像(V Flow)技术在测量健康成年人颈动脉壁面剪应力(WSS)中的一致性。方法于2021年2月至2021年3月招募健康成年志愿者20人,由2名不同年资的超声医师使用配备V Flow功能的Mindray Resona 7超声仪和3~9 MHz线阵探头进行双侧颈动脉扫查,分别采集双侧颈总动脉远段、颈总动脉分叉至颈内动脉起始部两段动脉的动态V Flow图像,测量两侧颈总动脉远段的近心端、远心端、分叉处及颈内动脉起始部的前、后壁的WSS,使用组内相关系数(ICC)和Bland-Altman图评估组内一致性及组间一致性。结果双侧颈动脉前、后壁的4个不同节段之间WSS值差异均有统计学意义(P<0.05)。高年资超声医师2次测量结果的一致性结果显示,左侧颈总动脉远段的远心端一致性极好(ICC 0.779),右侧颈总动脉远段的近心端(ICC 0.605)、远心端(ICC 0.585)、颈内动脉起始部(ICC 0.457)、左侧颈总动脉分叉处(ICC 0.606)及颈内动脉起始部(ICC 0.702)一致性均较好;不同年资超声医师的测量结果显示,仅右侧颈总动脉分叉处(ICC 0.486)及左侧颈总动脉远段的远心端(ICC 0.576)一致性较好。结论V Flow技术可显示不同位点间颈动脉WSS之间的差异,其组内一致性较好,但在不同年资超声医师间存在一定的差异。 展开更多
关键词 颈动脉 动脉粥样硬化 壁面剪应力 V flow成像技术
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基于Moldflow软件对薄壁件某塑料喷嘴的注塑方案优化研究
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作者 袁志华 符烜赫 袁博 《机械工程师》 2024年第3期14-17,共4页
喷嘴注塑产品的质量和性能很大程度上由注塑方案和工艺参数所决定,不当的注塑方案和工艺参数会导致充填不足、熔接线过多、翘曲变形量大等问题。为了可以减少生产周期,节约生产成本,利用三维软件UG对喷嘴进行建模,基于模流分析软件Moldf... 喷嘴注塑产品的质量和性能很大程度上由注塑方案和工艺参数所决定,不当的注塑方案和工艺参数会导致充填不足、熔接线过多、翘曲变形量大等问题。为了可以减少生产周期,节约生产成本,利用三维软件UG对喷嘴进行建模,基于模流分析软件Moldflow软件对喷嘴注塑产品进行分析和优化,通过比较点浇口和侧浇口两种方案的分析结果,最终确定该产品点浇口的方案更好。并通过设计正交实验,得到优化后的工艺参数。 展开更多
关键词 喷嘴 MOLDflow 模流分析 浇口位置 正交优化
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基于FLOW3D的集成式水下基盘泥沙冲淤三维数值模拟
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作者 薛强 高博远 +3 位作者 段辰宇 张子涵 陈同庆 张庆河 《水道港口》 2024年第3期333-338,414,共7页
泥面下集成式水下基盘是为开采渤海通航区等海域油气资源而提出的新型基盘,其基坑周围局部冲淤是工程实践关注的问题之一。基于不可压缩粘性流体运动的Navier-Stokes方程建立泥面下集成式水下基盘基坑周围三维水动力数学模型,对不同粒... 泥面下集成式水下基盘是为开采渤海通航区等海域油气资源而提出的新型基盘,其基坑周围局部冲淤是工程实践关注的问题之一。基于不可压缩粘性流体运动的Navier-Stokes方程建立泥面下集成式水下基盘基坑周围三维水动力数学模型,对不同粒径和不同流速情况下的局部冲淤进行了模拟。结果表明:泥沙粒径为0.005 mm时,由于泥沙较难起动,基坑附近局部冲淤较小。粒径分别为0.05 mm和0.1 mm时,在典型流速作用下,基盘附近可分别形成1 m左右和4 m左右的淤积。 展开更多
关键词 水下基盘 数值模拟 局部冲淤 三维水动力 冲刷 flow3D
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基于MoldFlow太阳能储能系统下盖成型模拟及应用
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作者 周先保 胡清根 傅海勇 《模具制造》 2024年第2期36-38,共3页
以太阳能储能系统下盖模流分析为例,反复修改流道和浇口截面尺寸与长度以及主流道位置,确定流道尺寸。运用MoldFlow对设计好的流道进行充填分析,以使成型达到流动平衡,并进行冷却、翘曲分析,预测成型缺陷,提出解决措施,为模具设计提供... 以太阳能储能系统下盖模流分析为例,反复修改流道和浇口截面尺寸与长度以及主流道位置,确定流道尺寸。运用MoldFlow对设计好的流道进行充填分析,以使成型达到流动平衡,并进行冷却、翘曲分析,预测成型缺陷,提出解决措施,为模具设计提供浇注系统和冷却系统方案和注射成型工艺参数,并应用于模具设计和实际生产。 展开更多
关键词 太阳能储能系统下盖 流动平衡 成型缺陷
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Analysis and experimental study on resistance-increasing behavior of composite high efficiency autonomous inflow control device
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作者 Liang-Liang Dong Yu-Lin Zhang 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期1290-1304,共15页
Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir. By water coning, we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks th... Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir. By water coning, we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks through to the wellbore. Autonomous inflow control device(AICD) is an important instrument maintain normal production after bottom water coning, however, the resistance increasing ability of the swirl type AICD is insufficient at present, which seriously affects the water control effect. Aiming this problem, this paper designs a multi-stage resistance-increasing and composite type AICD. The separation mechanism of oil-water two phases in this structure, the resistance form of oil-water single phase and the resistance-increasing principle of water phase are analyzed. Establishing the dual-phase multi-stage separation and resistance-increasing model, and verified by measuring the throttling pressure drop and oil-water volume fraction of the AICD, it is found that the composite type AICD has the effect of ICD and AICD at the same time, which can balance the production rate of each well section at the initial stage of production, delay the occurrence of bottom water coning. In the middle and later stages of production, water-blocking can be effectively increased to achieve water control and stable production.After structural sensitivity analysis, the influence law of various structural parameters on the water control performance of composite AICD was obtained. The simulation calculation results show that,compared with the existing swirl type AICD, composite AICD has higher sensitivity to moisture content,the water phase throttling pressure drop is increased by 4.5 times on average. The composite AICD is suitable for the entire stage of horizontal well production. 展开更多
关键词 Water control flow separation flow resistance-increasing AICD device Simulation and experiment
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A transient production prediction method for tight condensate gas wells with multiphase flow
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作者 BAI Wenpeng CHENG Shiqing +3 位作者 WANG Yang CAI Dingning GUO Xinyang GUO Qiao 《Petroleum Exploration and Development》 SCIE 2024年第1期172-179,共8页
Considering the phase behaviors in condensate gas reservoirs and the oil-gas two-phase linear flow and boundary-dominated flow in the reservoir,a method for predicting the relationship between oil saturation and press... Considering the phase behaviors in condensate gas reservoirs and the oil-gas two-phase linear flow and boundary-dominated flow in the reservoir,a method for predicting the relationship between oil saturation and pressure in the full-path of tight condensate gas well is proposed,and a model for predicting the transient production from tight condensate gas wells with multiphase flow is established.The research indicates that the relationship curve between condensate oil saturation and pressure is crucial for calculating the pseudo-pressure.In the early stage of production or in areas far from the wellbore with high reservoir pressure,the condensate oil saturation can be calculated using early-stage production dynamic data through material balance models.In the late stage of production or in areas close to the wellbore with low reservoir pressure,the condensate oil saturation can be calculated using the data of constant composition expansion test.In the middle stages of production or when reservoir pressure is at an intermediate level,the data obtained from the previous two stages can be interpolated to form a complete full-path relationship curve between oil saturation and pressure.Through simulation and field application,the new method is verified to be reliable and practical.It can be applied for prediction of middle-stage and late-stage production of tight condensate gas wells and assessment of single-well recoverable reserves. 展开更多
关键词 tight reservoir condensate gas multiphase flow phase behavior transient flow PSEUDO-PRESSURE production prediction
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